Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C3/00—Selection of compositions for coating the surfaces of moulds, cores, or patterns
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C9/00—Moulds or cores; Moulding processes
  • B22C9/12—Treating moulds or cores, e.g. drying, hardening
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/24—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials for applying particular liquids or other fluent materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C9/00—Moulds or cores; Moulding processes
  • B22C9/10—Cores; Manufacture or installation of cores
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
  • C04B35/16—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silicates other than clay
  • C04B35/18—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silicates other than clay rich in aluminium oxide
  • C04B35/195—Alkaline earth aluminosilicates, e.g. cordierite or anorthite
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  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
  • C04B35/48—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zirconium or hafnium oxides, zirconates, zircon or hafnates
  • C04B35/481—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zirconium or hafnium oxides, zirconates, zircon or hafnates containing silicon, e.g. zircon
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  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/62222—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products obtaining ceramic coatings
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
  • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
  • C04B35/632—Organic additives
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
  • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
  • C04B35/632—Organic additives
  • C04B35/634—Polymers
  • C04B35/63404—Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C04B35/63416—Polyvinylalcohols [PVA]; Polyvinylacetates
• • C—CHEMISTRY; METALLURGY
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  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
  • C04B41/009—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone characterised by the material treated
• • C—CHEMISTRY; METALLURGY
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  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
  • C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
  • C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
  • C04B41/5024—Silicates
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
  • C04B41/60—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only artificial stone
  • C04B41/61—Coating or impregnation
  • C04B41/65—Coating or impregnation with inorganic materials
  • C04B41/68—Silicic acid; Silicates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/34—Silicon-containing compounds
  • C08K3/36—Silica
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
  • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
  • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
  • C04B2235/3231—Refractory metal oxides, their mixed metal oxides, or oxide-forming salts thereof
  • C04B2235/3244—Zirconium oxides, zirconates, hafnium oxides, hafnates, or oxide-forming salts thereof
  • C04B2235/3248—Zirconates or hafnates, e.g. zircon
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
  • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
  • C04B2235/34—Non-metal oxides, non-metal mixed oxides, or salts thereof that form the non-metal oxides upon heating, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
  • C04B2235/3418—Silicon oxide, silicic acids, or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
  • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
  • C04B2235/34—Non-metal oxides, non-metal mixed oxides, or salts thereof that form the non-metal oxides upon heating, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
  • C04B2235/3427—Silicates other than clay, e.g. water glass
  • C04B2235/3463—Alumino-silicates other than clay, e.g. mullite
  • C04B2235/3481—Alkaline earth metal alumino-silicates other than clay, e.g. cordierite, beryl, micas such as margarite, plagioclase feldspars such as anorthite, zeolites such as chabazite
• • C—CHEMISTRY; METALLURGY
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  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
  • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
  • C04B2235/42—Non metallic elements added as constituents or additives, e.g. sulfur, phosphor, selenium or tellurium
  • C04B2235/422—Carbon
  • C04B2235/425—Graphite
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
  • C04B2235/96—Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
  • C04B2235/9669—Resistance against chemicals, e.g. against molten glass or molten salts
  • C04B2235/9676—Resistance against chemicals, e.g. against molten glass or molten salts against molten metals such as steel or aluminium

Definitions

• a sizing composition for the foundry industry containing particulate amorphous silica and acid
• the present invention relates to a sizing composition for use in the foundry, in particular comprising particulate, amorphous silicon dioxide (Si0 2 ) and an aqueous phase having a pH of at most 5, preferably of at most 4, as well as sized, water glass bonded foundry shaped bodies, in particular sized, water glass bonded Foundry molds and foundry cores, each comprising a sizing composition according to the invention.
• the invention relates to the use of a sizing composition according to the invention for the production of a coating on a water-glass-bonded foundry molded body and a process for the preparation of a water-glass-sized foundry molded body (mold or core).
• the invention likewise relates to a kit, including, inter alia, a sizing composition according to the invention.
• the invention is defined in the appended claims.
• Casting in a lost form is a common process for producing near-net shape components, especially in metal casting. After casting, the mold is destroyed and the casting is removed. Shapes are negatives, they contain the emptying cavity, which results in the casting to be produced.
• the inner contours of the future casting can be formed by cores. In the preparation of In the mold, the cavity can be formed into the molding material by means of a model of the casting to be manufactured. Cores are usually formed in a separate core box.
• foundry molds also referred to as “molds” for the purposes of the present invention
• foundry cores also referred to as “cores” for purposes of the present invention
• predominantly refractory granular materials such as e.g. washed, classified quartz sand used.
• suitable molding materials which are known per se are e.g. Zirconsande, Chromitsande, chamois, olivine sands, feldspat ambience sands and Andalusitsande.
• a molding material may also be a mixture of various of the above or other preferred molding materials.
• the refractory molding material is preferably in free-flowing form, so that it can be filled into a suitable mold and compacted therein.
• the molding base material or the corresponding molding material mixture is compacted in order to increase the strength of the casting mold.
• the mold bases are bound with inorganic or organic molding binders (binders).
• binding By the molding material binder a firm cohesion between the particles of the molding material is generated, so that the foundry mold obtains the required mechanical stability.
• the production of molds and cores takes place in industrial practice regularly and advantageously in shooting machines or molding machines, in which a compression of the particulate components and a hardening of the binder takes place; this also applies to the forms and cores used in the context of the present invention.
• both organic and inorganic molding material binders can be used, the curing of which can be carried out in each case by cold or hot processes.
• the skilled worker refers to processes which are carried out essentially at room temperature without heating the foundry mold.
• the curing is usually carried out by a chemical reaction, which is triggered for example by the fact that a gas is passed as a catalyst after molding through the molding mixture to be cured, which contains the molding material and the molding material binder.
• the molding material mixture is heated to a sufficiently high temperature after molding to expel, for example, the solvent contained in the molding material binder and / or to initiate a chemical reaction by which the molding material binder is cured, for example, by crosslinking.
• molding material binders which are based on inorganic materials and at most contain a very low proportion of organic compounds.
• Such binder systems have long been known, for example, from the documents GB 782205 A, US 6972059 B1, US 5582232 A, US 5474606 A and US 7022178.
• inorganic molding material binder denotes a molding material binder, which consists entirely predominantly, preferably more than 95 wt .-%, preferably more than 99 wt .-%, most preferably completely of water and inorganic materials, so that the proportion on organic compounds in such an inorganic molding material binder is preferably less than 5 wt .-%, preferably less than 1 wt .-% and most preferably 0 wt .-%.
• inorganically bound in the context of the present text means that a mold or a core has been bonded with an inorganic molding material binder (as defined above).
• alkali water glass Of particular importance as a component of inorganic molding binders is alkali water glass.
• glassy, ie amorphous, water-soluble sodium, potassium and lithium silicates, their mixtures and the corresponding aqueous solutions are called.
• water glass refers to those amorphous, water-soluble sodium, potassium and / or lithium silicates and / or their aqueous solutions and / or mixtures of the aforementioned silicates and / or their solutions, each having a molar modulus (molar ratio) of Si0 2 to M 2 O in the range of 1.6 to 4.0, preferably in the range of 1.8 to 2.5, where M 2 0 denotes the total amount of lithium, sodium and potassium oxide.
• water glass bonded means that a foundry molded body, in particular a mold or a core, has been produced or can be produced using a molding material binder which comprises water glass or consists of water glass.
• a molding material mixture which comprises, in addition to a refractory molding base, a water glass-based molding material binder and a particulate metal oxide, wherein precipitated silica or fumed silica is preferably used as the particulate metal oxide.
• Inorganic molding material binders also have disadvantages compared to organic molding material binders.
• foundry molds or cores made with known inorganic molding binders have relatively little or no stability to atmospheric moisture or to water or aqueous moisture.
• storage of such foundry molds or cores over a relatively long period of time, as is customary with organic molding material binders is not reliably possible.
• finishing in foundry technology should fulfill the following functions known to the person skilled in the art: improvement of the smoothness of the casting surface;
• binders for short
• biocides and / or wetting agents and / or rheological additives Ready-to-use sizing compositions for coating molds and cores
• a carrier liquid eg an aqueous (ie water-containing) carrier liquid or a non-aqueous (ie no water-containing) carrier liquid, for details see with regard to the carrier liquid he downstairs.
• the size or the size composition is applied by a suitable application method, for example spraying, dipping, flooding or brushing on the inner contour of the casting mold or on the core and dried there, so that a size coat or size film is formed.
• a suitable application method for example spraying, dipping, flooding or brushing on the inner contour of the casting mold or on the core and dried there, so that a size coat or size film is formed.
• the drying of the size coat may be accomplished by the application of heat or radiant energy, e.g. by microwave radiation, or by drying in the room air done.
• the drying may also be carried out by burning off these compounds.
• refractory refers to masses, materials and minerals which, at least for a short time, can withstand the temperature load during casting or during the solidification of an iron melt, usually cast iron. Materials and minerals, which can withstand the pouring heat of a steel melt in the short term. The temperatures that can occur when casting molten steel, are usually higher than the temperatures that can occur during the casting of iron or cast iron melts. Refractory materials, materials and minerals (refractories) and high-refractory materials, materials and minerals are known in the art, for example from DIN 51060: 2000-06.
• the refractory materials used in sizing compositions are usually mineral oxides, silicates or clay minerals.
• refractory materials which are also suitable for the purposes of the present invention are quartz (silica), aluminum oxide, zirconium dioxide, aluminum silicates, phyllosilicates, zirconium silicates, olivine, talc, mica, Graphite, coke, feldspar, diatomite, kaolins, calcined kaolins, metakaolinite, iron oxide, chromite and bauxite, each of which can be used individually or in any combination with each other.
• the refractory material serves, inter alia, to close the pores in a foundry mold or a core against the penetration of the liquid metal.
• the refractory material is usually provided in powder form. Unless stated otherwise, pulverulent refractories then have an average particle size (preferably measured by means of light scattering according to ISO 13320: 2009-10) in the range from 0.1 to 500 ⁇ m, preferably in the range from 1 to 200 ⁇ m. Suitable refractory materials are in particular those materials which have melting points which are at least 200 ° C. above the temperature of the particular molten metal used and / or which do not react with the molten metal.
• the refractories are usually dispersed in a carrier liquid.
• the carrier liquid is one or the constituent of a sizing composition which is preferably liquid under normal conditions (20 ° C and 1013.25 hPa) and / or vaporizable at 160 ° C and normal pressure (1013.25 hPa).
• Preferred carrier liquids which are also suitable for the purposes of the present invention are selected from the group consisting of water and organic carrier liquids and mixtures thereof with one another and / or with further constituents.
• Suitable organic carrier liquids are preferably alcohols, including polyalcohols and polyether alcohols. Preferred alcohols are ethanol, n-propanol, isopropanol (2-propanol), n-butanol and glycol. Water and aqueous mixtures (including aqueous solutions) are often preferred as a carrier liquid.
• Sizing binders are primarily used to fix the refractory materials contained in a sizing composition on the molding material.
• binders which are also suitable in the context of the present invention are synthetic resins (organic polymers) or synthetic resin dispersions, such as polyvinyl alcohols, polyacrylates, polyvinyl acetates and / or corresponding copolymers of the abovementioned polymers. Polyvinyl alcohols are preferred. Natural resins, dextrins, starches and peptides are also suitable as binders.
• Biocides prevent bacterial infestation.
• biocides which are also suitable for the purposes of the present invention are formaldehyde, 2-methyl-4-isothiazolin-3-one (MIT), 5-chloro-2-methyl-4-iosthiazolin-3-one (CIT) and 1, 2 -Bisisothiazolin-3-one (BIT).
• the biocides preferably the said individual biocides, are usually in one Total amount of 10 to 1000 ppm, preferably used in an amount of 50 to 500 ppm, each based on the total mass of the ready-to-use sizing composition (which is intended to be applied directly to a mold or a core).
• Rheological additives adjusting agents are used to adjust the flowability of the size desired for processing.
• inorganic adjusting agents are, for example, swellable clays, such as sodium bentonite or attapulgite (Palygorskit).
• suitable organic adjusting agents are, for example, swellable polymers call, such as cellulose derivatives, in particular carboxymethyl, methyl, ethyl, hydroxyethyl and hydroxypropyl cellulose, mucilages, polyvinylpyrrolidone, pectin, gelatin, agar-agar, polypeptides and / or alginates.
• rheological additives or setting agents are preferred ingredients of the size composition according to the invention.
• inorganic mold-material binders in particular water-glass-containing molding material binders, should become increasingly important in the area of steel and iron casting in the production of molds and cores.
• This particular problem known in the foundry art see, e.g., WO 00/05010 A1
• the document DE 10 2006 040 385 A1 discloses temperature-stable BN mold release layers based on ceramic and glassy binders; however, the document does not disclose the use for inorganically bound forms or cores (based on corresponding granular molding bases) for use in the foundry.
• the German Patent and Trademark Office has researched the prior art for the priority application for the present application: DE 10 2006 040 385 A1, DE 10 2006 002 246 A1, DE 10 2005 041 863 A1 and DE 15 08 913 A.
• a further object of the present task was to produce sized inorganically bonded foundry moldings, in particular foundry molds and / or foundry cores, to provide each of which comprise a sizing composition to be given according to the invention.
• a further object of the present invention was to provide a corresponding process for the preparation of an inorganic bonded foundry body sized with a water-containing size.
• an object of the present invention was a kit, i.a. containing a sizing composition to be given according to the invention.
• sizing compositions according to the invention uses according to the invention, inventive methods, coated forms or cores according to the invention and kits according to the invention are described, which "comprise” or “contain” specific embodiments, constituents or features, in each case also the corresponding ones to be understood to a narrower extent
• the primary object and other aspects of the general object given above are achieved by comprising a sizing composition (a) an aqueous phase having a pH of at most 5, preferably at most 4,
• aqueous sizing composition according to the invention, binding structures in the alkali silicate framework of the water-glass-bound, sifted foundry shaped body (mold or core) are attacked, however, possibly resulting weakening of the bonding structure by a further chemical reaction , such as an acid-base reaction, are removed again in the presence of the particulate amorphous silica, as a result of which an increased strength of such sized, water-glass bonded foundry moldings is achieved in comparison with the prior art.
• a further chemical reaction such as an acid-base reaction
• the pH in a sizing composition is determined in each case from the suspension, preferably according to the standard method DIN 19260: 2012-10.
• the particulate amorphous silica (component (b)) does not count among the "further” refractories of component (c) for the purposes of the present invention.
• Precipitated silica is known per se and can be obtained, for example, in a manner known per se by reaction of an aqueous alkali metal silicate solution with mineral acids: The resulting precipitate is then separated, dried and optionally ground. Fumed silicas are also known per se and can preferably be obtained in known manner at high temperatures by coagulation from the gas phase.
• the production of fumed silica can be carried out, for example, by flame hydrolysis of silicon tetrachloride, or for the purposes of the present invention preferably in an electric arc furnace by reduction of silica sand with coke or anthracite to silicon monoxide gas with subsequent oxidation to silica.
• amorphous particulate silica of the present invention is that of zirconia production.
• Another, known per se, possibility of producing particulate amorphous silica is the spraying of a silicon dioxide melt: the primary, amorphous silicon dioxide particles do not arise here (as in other preferred production processes) through a milling process.
• one or more substances are preferably selected from the group consisting of quartz, aluminum oxide, zirconium dioxide, aluminum silicates, phyllosilicates, zirconium silicates, olivine, talc, mica, graphite, coke, feldspar, diatomite, kaolins, calcined kaolins, metakaolinite, iron oxide and bauxite.
• the sizing composition according to the invention is particularly suitable for producing a coating on a water-glass-bonded form or a water-glass-bonded core, preferably on such water-glass-bonded forms or cores, which contain at least a proportion of particulate, amorphous silicon dioxide.
• Waterglass-bonded shapes and cores including those containing particulate amorphous silica (in addition to conventional molding bases), and their preparation, are known per se, for example from documents WO 2006/024540 and WO 2009/056320.
• the aforementioned forms and cores known per se are suitable for the purposes of the present invention.
• the primary particles of the particulate amorphous silica of the component (b) (i) are spherical and have a sphericity of 0.9 or more as determined by evaluation of two-dimensional microscopic images.
• Modern commercially available electron microscopic or light microscopic systems enable a digital image analysis and thus a comfortable determination of the particle shape. Digital image analysis is preferred for studies of sphericity.
• component (c) comprises one or more substances selected from the group consisting of quartz, alumina, zirconium dioxide, aluminum silicates, layered silicates, zirconium silicates, olivine, talc, mica, graphite, coke, feldspar, diatomite, Kaolins, calcined kaolins, metakaolinite, iron oxide and bauxite, and / or wherein component (a) comprises one or more acids, preferably having a pKa ⁇ 5, more preferably having a pKa ⁇ 4, selected from the group consisting of inorganic and organic acids, wherein the organic acids are preferably selected from the group consisting of mono-, di- and tricarboxylic acids, preferably at 25 ° C and 1013 mbar solid mono-, di- and tricarboxylic acids, more preferably citric acid and oxalic acid, and / or wherein the inorganic acids are
• the "D90 value" of the primary particles of the particulate, amorphous silicon dioxide denotes their particle size distribution
• the particle size distribution is determined in a manner known per se by laser diffraction, preferably according to the standard method according to DIN ISO 13320: 2009-10
• the cumulative frequency distribution of the volume-averaged size distribution function indicates that 90% by volume of the primary particles have a particle size which is equal to or less than the stated value (eg 10 ⁇ m) "Mastersizer 3000" from Malvern, Great Britain, preferably of the “Coulter LS 230" type from Beckman Coulter, USA, the measurement preferably being carried out with the aid of "Polarization Intensity Differential Scattering" ("PIDS”) technology.
• PIDS Polyization Intensity Differential Scattering
• the term "secondary constituent" means that the particulate amorphous silica of component (b) contains only minor amounts of such secondary constituents which are still present as impurities or adhesions from previous production and / or processing processes of the particulate, amorphous
• the secondary components mentioned are preferably in an amount of not more than 18% by weight (or by weight), more preferably in an amount of not more than 12% by weight, most preferably in an amount of not more than 8% by weight , in each case based on the total mass of the particulate amorphous silicon dioxide of component (b).
• One of the aforementioned minor components in component (b) may be a Lewis acid. However, several Lewis acids and / or mixtures thereof may also be included.
• Lewis acid is understood to mean an acid according to the concept proposed by GN Lewis, according to which an acid is an electron pair acceptor, ie a molecule or ion with incomplete noble gas configuration, which is one from a Lewis base
• a Lewis acid is electrophilic, whereas a Lewis base is nucleophilic, which means that molecules and ions can also be considered as acids that are not acids according to classical ideas.
• Preference is furthermore given to a sizing composition according to the invention comprising one or more or all of the following constituents: one or more biocides, one or more wetting agents, one or more rheological additives, and one or more binders, preferably polyvinyl alcohol.
• an inventive or preferred sizing composition wherein the ratio of the total mass of inorganic and organic acids in the aqueous phase (a) relative to the total mass of the sizing composition in the range of 0, 1 to 10%, preferably in the range of 1 to 5%, preferably in the range of 2.5 to 3.5%, and or wherein the ratio of the mass of the water to the total mass of the aqueous phase of constituent (a) is greater than 50%, preferably greater than 70%, more preferably greater than 90%, and / or wherein the sizing composition has a solids content of less than 80% by weight.
• the sizing composition has a proportion of particulate amorphous silica of component (b) in the range of 1 to 30 wt .-%, preferably 5 bis 20 wt .-%, particularly preferably 8 to 17 wt .-%, based on the total mass of the sizing composition and / or wherein the sizing composition is a total amount of particulate, amorphous silica of component (b) and of other refractory constituents of component (c) in the range from 25% by weight to 80% by weight, preferably from 30 to 60% by weight, particularly preferably from 45 to 55% by weight on the total mass of the size composition.
• a further preferred embodiment is an inventive or preferred sizing composition according to the invention comprising one or more binders, preferably comprising polyvinyl alcohol, in a total amount of not more than 2% by weight, preferably in an amount in the range of from 0.05 to 0.80% by weight .-%, based on the total mass of the sizing composition.
• the sizing composition according to the invention or to be used according to the invention is preferably ready for use, ie it is intended to be applied directly to a casting mold or to a core.
• the sizing composition according to the invention or to be used according to the invention can also be in the form of a concentrate, then it is intended to be diluted to a casting mold or a core before application, in particular by adding water or an aqueous mixture. This applies to all embodiments of the present invention, unless stated otherwise or specified.
• the expert decides in each case whether a sizing composition is ready for use or should still be diluted.
• Another object of the present invention is the use of a sizing composition of the invention described above, including its preferred embodiments, for the production of a coating on a waterglass-bonded or waterglass bonded core for use in the foundry.
• the invention further relates to the use of particulate, amorphous silicon dioxide in a sizing composition, preferably in a sizing composition as disclosed above as being according to the invention and / or as being preferably disclosed in accordance with the invention
• the water-glass-bonded core or the water-glass-bonded form preferably contains particulate, amorphous silicon dioxide.
• a "high flexural strength” means a bending strength of a foundry molded body, preferably a core or a mold, which allows a practical handling of the foundry molded body without breaking it.
• the invention also provides a process for producing a water-glass-bonded form sized with a water-containing size, preferably a mold having a high flexural strength, or a water-glass-bonded core sized with an aqueous-containing size, preferably such a core having a high flexural strength, for use in the foundry, with the following steps:
• step (1) on the provided or prepared mold or core provided or manufactured.
• Preferred is a process according to the invention, wherein the provided or prepared unsized or uncoated core contains particulate, amorphous silica, and / or wherein the unsupported, waterglass bonded or unsupported, waterglass bonded core in step (2) Curing a prepared or prepared molding material mixture
• esters or phosphates by the addition of esters or phosphates or
• phosphates which are suitable for curing, for example, aluminum phosphates can be used.
• the sizing composition provided or prepared in step (1) of the process of the invention may be prepared by methods known in the art. For example, water can be initially charged in a suitable amount and the further constituents for the preparation of the size composition can then be added in any desired amount to this original while stirring with a suitable stirrer such as a high-shear stirrer, for example a gear stirrer or a dissolver stirrer. If necessary, ingredients may be digested before or during the addition in a manner known per se. Thus, for example, optionally one or more rheological additives can be digested using a high shear stirrer, before or after addition to the water receiver, and individually or together with one or more refractories.
• a suitable stirrer such as a high-shear stirrer, for example a gear stirrer or a dissolver stirrer.
• ingredients may be digested before or during the addition in a manner known per se.
• one or more rheological additives can be digested using
• the one or more refractories are not digested together with any added theological additives, they can also be broken up individually. and added to the water template. Then, for example, the further constituents of the sizing composition can then be added to the water template, optionally containing theological additives and / or refractories, in any order and preferably with stirring, preferably with a high-shear agitator, such as one or more acids.
• one or more sizing binders optionally one or more biocides, optionally one or more wetting agents, optionally one or more defoamers, optionally one or more pigments and / or optionally one or more dyes.
• the sizing composition provided or prepared in step (1) of the process of the invention may be ready for application to foundry moldings, that is, for example, in a concentration suitable for use as a dipping bath for molds or cores.
• the aforementioned sizing composition can also be prepared in a manner known per se, first as a concentrate, which is added later, e.g. just before the use of the sizing composition, e.g. by further adding water to a ready-to-use concentration (or consistency) which is then suitable for application to molds and / or cores.
• a ready-to-use size composition (intended to be applied directly to a casting mold or a core) is meant, unless expressly stated otherwise. It is usually not necessary to mix the individual constituents of the sizing composition according to the invention or to be used according to the invention directly on molds or cores only before an intended coating process; rather, the mixing can take place much earlier because the storage stability is the same as that according to the invention or according to the invention using sizing composition is high.
• the uncoated, preferably water-glass-bonded, or prepared or prepared unsized, preferably water-glass bonded, core prepared or prepared in step (2) of the process according to the invention can be prepared in a manner known per se, for example as in documents WO 2006/024540 or WO 2009 / 056320 described.
• the present invention also relates to a sized, water-glass-bonded form or a sized, water-glass bonded core for use in the foundry, comprising a sizing composition as described above as being preferred according to the invention and / or according to the invention.
• this mold and this core can be prepared by a method as described above according to the invention and / or as preferably described according to the invention for producing a water-glass-bonded form sized with a water-containing size or a glass-water-bonded core sized with an aqueous-containing size.
• the sizing composition according to the invention has, in particular, the following advantages over comparable sizing compositions known from the prior art and / or substantiates: improved strength of the sized forms and / or cores obtainable therewith, in particular of the sized inorganic inks prepared therewith, preferably the water-glass-bound shapes and / or cores produceable therewith; an improved storage stability of the thus produced sized forms and / or cores, in particular of the thus produced sized inorganically bound, preferably of water-sealable forms and / or cores produced therewith; an improved resistance to atmospheric moisture of the thus produced, sized molds and / or cores, in particular of the resulting sized, inwardly prepared, preferably water-glass-bound forms and / or cores produced thereby; an improved possibility of application to hot molds and / or cores (ie preferably to those molds and / or cores which have temperatures of more than 50 ° C, preferably temperatures in the range of 50 to 100 °
• SZ1 sizing composition
• SZ2 non-inventive comparative sizing compositions
• SZ3 non-inventive comparative sizing compositions
• the required amount of water was initially introduced into a beaker (batch size in each case about 2 kg of sizing composition as "concentrates", see Table 1), the theological additives and the refractory materials (phyllosilicates, zirconium flour, graphite) added and then with a high shear
• the further constituents of the size compositions were then added in the proportions indicated and the mixture was stirred for a further 2 minutes with a high-shear dissolver stirrer specified dilutable concentrates of sizing compositions.
• test cores (specimens) were prepared in a manner known per se (according to "core system 1" given in Table 4) in a core shooter from the company Multiserw (type LUT, Aeration pressure: 2 bar, shot time: 3.0 s, shooting pressure 4.0 bar).
• core system 1 the number of core shooters.
• the experimental kernels were treated with the o.g.
• test cores were each dried over a period of one hour, with their flexural strengths (in N / cm 2 , as defined in the leaflet R 202 of the Association of German foundry professionals, October 1978 issue) at different times during drying and then one hour after the end of the drying process with a standard tester of the type "Multiserw-Morek LRu-2e", each with a standard measuring program "Rg1v_B 870.0 N / cm 2 " (3-point bending strength).
• water-glass bonded test cores were prepared in a manner known per se (analogously to Example 2) and their flexural strengths were respectively unsized shortly after their preparation (one hour of storage, relative humidity in the range from 30 to 60%, temperature in Range of 20 to 25 ° C) as stated above, cf. Table 3 (entry "unsatisfied after 1 h").
• the core system 1 consisted only of the components molding material, binder and additive, as indicated in Table 4:
• the binder specified for the core system 1 in Table 4 was a commercially available alkali-waterglass binder "Cordis® 851 1" (Hüttenes-Albertus Chemische Werke GmbH).
• the additive given for core system 1 in Table 4 was a commercially available binder additive with the main constituent (> 95% by weight) of particulate, amorphous silicon dioxide, "Anorgit® 8396” (Hüttenes-Albertus Chemische Werke GmbH).

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